That is up to you to decide. However, I would recommend to learn the E major scale, and after that the B major (german H) - they both fit very well into the hand, and are more comfortable to play than the C major, but still keeping the "standard" fingering (1-2-3-1-2-3-4). Then later you can go on to learn all the other scales. Sounds like a lot of work but trust me, when you get a few down the others will be much easier - and if you do practise all scales (you can for example practise a different scale every day or whatever suits you the best) you will gain tremendously and it will help you a lot in playing other stuff.
All the best
V